Field Exercise #3

Re-Storying the West

Natural History Component

Developing an ethogram


Animals are capable of using behaviors to satisfy their biological needs. Behaviors are motions that are under control of the nervous system and the muscles. To accomplish even the most simple behaviors often requires the coordination of many muscles and many more neurons. Behaviors can be amazingly simple or have mind boggling complexity. They can be simple reflexes, such as a knee jerk in response to a tap on the patella (knee cap), the turning toward light by a Euglena, or the withdrawal of a monkey's hand from a painful stimulus. Alternatively, they can involve large areas of the cerebral cortex and last long periods of time. Examples of complex behaviors are a sandhill crane's courtship dance, a coyote howling and the breaching behaviors of whales. Many complex behaviors can be divided into a number of fairly regular, identifiable components. These behaviors are called 'stereotyped behaviors' because the vary little among individuals of a species and are very similar each time they are performed.

Many behaviors are expensive in terms of energy. For example, the calling a frog does at a breeding pond is the most energetic activity it will engage in during its lifetime. It is thought that the performance of energetically expensive behaviors likely contributes to an individual's fitness, otherwise there would likely have been selection to remove the behavior from the population--frivolous, costly behaviors would expend energy that could otherwise be used for producing offspring. Often, the inability to perform even a simple behavior can lead an animal to an early death or failure to reproduce. Thus, because behaviors often contribute to the fitness of an individual, they form part of the means by which an animal is adapted to its environment.

The behaviors used to satisfy the needs of animals are varied. For example, an animal may have different behaviors involved in feeding, escape, courtship, copulation, and grooming. One of the most interesting use of behaviors is for communicating information. The existence of persistent groups of mobile animals depends on communication behaviors for maintaining the cohesiveness of the group, coordinating movements, avoiding predators and maintaining a social structure. Similarly, successful mating among individuals of many species depends on the performance of a number of behaviors before individuals can copulate, i.e. courtship behavior. Absence of some behaviors may cause an individual to refuse copulatory attempts, or a missing behavior may have been necessary to elicit copulation from a partner.

Many questions have been asked about the significance of behaviors, their meaning. Sometimes we know full well what a certain behavior or behavior set signifies, for example when a dog pulls it's ears back, bares it's teeth and growls. The significance of other more-subtle behaviors is less obvious, for example when a dog lifts it's leg against a tree but does not urinate. Are we sure that it signifies 'oops, guess I didn't have to...', or is their something more to it? One way people who study animal behavior address the meaning or information content of behaviors is to determine the social context of the performance of the behavior. In doing this, they usually don't study just one behavior but instead address a suite of behaviors and quantify the frequency of the performance of different behaviors in relation to the changing social context of the animal. As a prelude to this, a researcher will often make a complete list of the behaviors performed by the animal. This list is known as an ethogram and this is the object of this exercise.

Goal and objective

The goal of this exercise is to motivate you to pay closer attention to the animate world around you and to improve your observational powers. The exercise that will help you develop in this respect is to make an ethogram (a list) of the behaviors of the common crows on campus. You should be prepared to make as complete an ethogram as possible. You should include both social behaviors and ones that solitary birds perform. You should try to include behaviors involved in feeding, threat, courtship, 'playing', mating, alarm, interacting with other species, dominance, in short everything. Try to identify the different calls made by crows. Calls may have associated physical movements that you should describe. The behaviors you identify should be distinct and identifiable by another observer. One way to check yourself is after you've got your list, sit and watch a crow or two with a friend. Can your friend and you agree on the behaviors? How many can you come up with? How many distinct calls do crows make? Be especially careful to note all stereotyped behaviors. Remember, these are ones that are essentially identical each time they are performed. For example, a 'tail-shake' or 'wing stretch-flapping'. Give each stereotyped behavior a name. Make sure to break down complex behavior into component stereotyped behaviors if it is possible. See if you can identify in the crow a series of stereotyped behaviors that occur as a particular sequence. Such a sequence is called a 'fixed action pattern'. Often, fixed action patterns serve important functions, such as threat, courtship, or appeasement. As such, they may be under strong influence of selection. Your list of stereotyped behaviors and fixed action patters is your ethogram.

A helpful prelude to doing this exercise will be to do a little pre-exercise. Outside the CAB, watch a person light a cigarette. What are the component, highly repeated (stereotyped) behaviors that go into lighting a cigarette?

Transcribe your field notes on the crow's behaviors into a species account on the common crow in your journal. You should then be aware that other animals you observe have their own stereotyped behaviors.


Note: We will likely discuss the results of the first three exercises sometime next week as a big group.

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